Winter cover crops effects on soil microbial characteristics in sandy areas of Northern Shaanxi, China

摘要

In sandy areas of Northern Shaanxi, after potato harvest, there are large areas of soil exposed to wind erosion from winter to spring, leading to degradation of soil quality. Planting cover crops in fallow fields is considered effective to improve soil biological properties; however, there is scarce study on the effect of winter cover crops on fallow soils in this region. In the study lasting from 2017 to 2019, four winter cover crops, i.e., alfalfa (AC), sweetclover (SC), winter wheat (WC), and ryegrass (RC), as well as bare land (CK), were used to study the effect of winter cover crops on soil microbial characteristics. The experiment showed that the soils in AC treatment had the highest values of microbial biomass N (MBN) content, dehydrogenase and urease activities, bacteria colonies, and Shannon and Richness indices. The soils in SC treatment had the maximum values of microbial biomass C (MBC) content, protease activity, fungi colonies, and Simpson index. Under AC and SC treatments, microbial communities in soil showed the highest percentage of carbon source utilization for amino acids, carbohydrates, and amines. Alfalfa and sweetclover as cover crops were helpful to improve the activity and diversity of soil microorganisms, exerting a positive effect on soil quality. This finding is of great significance for improving the methods of mitigating soil degradation in winter fallow fields of Northern Shaanxi, China.